This is an open-label, randomized, four-way crossover pharmacokinetic study in liver transplant recipients. The primary objective of this study is to determine a dose of valganciclovir given once daily to liver transplant recipients that will provide a ganciclovir exposure similar to the exposure provided by IV ganciclovir given at 5 mg/kg/day and oral ganciclovir given at 3000 mg/day. Adult liver allograft recipients who have stable liver and renal function and have no major ongoing or unstable complications of transplant may be eligible to participate in this study. They must be seropositive for CMV, or if they are seronegative, must have received their organ from a seronegative donor. Subjects must not be considered to be at high risk of developing CMV disease. Up to 24 patients may be enrolled in this study at several medical centers. Up to six patients may be invited to participate in this study at the University of Wisconsin.